So, against my wishes my truck has been seeing a lot more short trips and shut offs than I like to bear, but I want to do the best I can for it. I have an onboard 1.5amp battery minder on it some nights to help when I don't need the block heater but I don't believe 12 hours overnight is enough time to charger 2 battery's at 1.5 amp. I've been looking at redoing my electrical under the hood and came across a NOCO G7200 12/24v 7.2amp smart charger that I think will put out the power to charge both batteries full overnight. Any thoughts on using this? Being a smart charger, plug and leave should be fine overnight and it even desulfates

 

Not sure what brand you have but they typically have lights to designate between charging and maintaining. Which mode is it in during the times your concerned? If it's maintain, you have nothing to worry about.

 

It is always in charge mode, I have a 185amp DC alt but I should have went bigger. Is the charger a better choice to get the battery's into float in a shorter time?

 

I got a 3 amp schaurer with a sears re-lable on it. Shows state of charge when hooked up and then will charge and then maintain. My truck sits more than its driven but batteries are sears and about 5 years old. Originals lasted about 7 years. Actually I have several and they supposedly will go to de-sulfate when required. I bought a battery tender last year that does desulfate for my rv also added a smart tender to the rv charge system to regulate the batery installed.

 

Two batteries in parallel is just a really large single battery from an electrical standpoint. A tender isn't even close to big enough to bulk charge and equalize. Their purpose is to prevent a charged battery from self-discharge over long periods of disuse. Some of them have protection circuitry to prevent excessive outgassing of electrolyte, they will switch to float automagically but the battery is not really charged up.

The rule of thumb for charger "sizing" is no more than about 20% of the Ah capacity of a battery (not CCA, Ah) is a nice slow charge. Also consider in cold weather the internal resistance of a battery increases, charge tables are temperature compensated for this reason. Determine your needs and monitor the voltage using an appropriately sized "dumb" charger for best results. The "smart" chargers have their place but don't ditch the old Schumacher just yet.

 

Going bigger on the alternator isn't necessarily the answer as the batteries only accept so much charge current based on their internal resistance. If after GP operation the batteries will only except 60a, an alternator that has the potential of 120a at that time isn't going to improve the situation.

If your time running isn't fully charging, and many can have that issue without knowing it, trying to charge overnight is a good practice. Manu of the battery information sites state that battery undercharge has a significant impact on battery life. I'm not familiar with that specific charger, but whatever size you need to get it done would be good. I've got a charger with desulphation capabilities and it's helped at the farm with equipment that gets run sporadically.

I put a battery tender on my truck during cold weather when it's going to sit for days and it stays in maintain mode. But my day travel is typically two runs of 45 minutes with only the two startups.

 

Not an expert but I always thought a longer charge at low amps is better for the batteries.

Mine normally takes about 12 hrs of charging and it's in float mode. I use a Battery Minder, not sure of the amps but I believe it's about 1.5.

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In the summer the battery minder worked fine, but the winter and short trips it just isn't keeping up, plus I don't have the ability to plug the charger in every night which doubles the issue. Just making sure the NOCO is an alright choice

 

So you might see me in other posts on this topic right now, as I had an intermittent battery light and have been doing some testing and checking of things. I also use a charger from time to time and what the other posters are telling you is right. I would recommend a smart charger that can float, bilk charge, and trickle charge and knows how to switch on its own.

I own a 2 amp, 12 amp charger which can do traditional and deep cycle batteries. When I put it on 2 amp I can measure as much as 3 amps charging when initially connected. This slowly drops to 1 amp, and then it shuts off and shows it has completed. I run a 230 amp alternator per my signature, over night on two batteries, it's complete in 12 hours. If I use the 12 amp setting its more like 4 to 5 hours, but at the 12 setting my batteries are often full enough that it will only push 8-9 amps, meter verified, and this slowly drops down to 4-5 amps and it is done in 4-5 hours.

I park in my garage so I can run the charger and the block heater(on a timer for 4 hours in the early morning) so that I can do both. Block heater uses about 9 amps, the charger at 2 amp setting is using less than that in AC amps, one 20 amp circuit will work fine unless ya ou have a weak breaker.

 

I'm going to spring for the NOCO 7.2amp smart charger then. I believe it is a 12 step charge with desulfation. When plugged in it is usually 12 hours so should be plenty of time for 7.2amps to charge from 75% batteries or so. Hope they aren't lower

 

a tender is fine for maintaining but to charge a dead battery you need more than 2 amps

 

That's what I figured too, a maintainer is best for keeping your battery full over a period of time, it lacks in charging ability unless left for a length of time. I'd rather have a quicker charger that guarantees me full batteries to help with the stop and starts in the -20 to -30 weather that we all know wrecks batteries

 

If your batteries are not completely recharged by the alternator you need to fix that problem rather than messing around with a battery maintainer.

 

The alternator is 185amp DC alt but it's the stop and starts in the cold that are draining the batteries, the alt charges fine but just doesn't have enough time. Sometimes the stops are inevitable, and I rather not let it run while I'm inside a building, call me paranoid

 

Your not paranoid. You have a good understanding of the situation.